Lie of the Thirteen (دروغ سیزده – Doruq e Sizda') is the Iranian version of the prank-playing April Fools' Day which is practiced on the first or the second day of April in Iran, on the day of Sizdah Be-dar.[4][5][6]

A ritual performed at the end of the picnic is to throw away the greenery (سبزه – Sabze) collected for Haft-Seen, the customary setting of Nowruz in Iran. Touching someone else's greenery on this day or bringing it back home is considered a bad omen.

Chahardah Be-dar (Persian: Čahārda' be Dar – چهارده به در‎‎) is the fourteenth day of Nowruz, which is celebrated only in Lorestan Province. Lurs stay home on the thirteenth day of Nowruz, referred to as the Strange Thirteen (سیزده غریب – Sizdah e Qarib) by them. Instead, they picnic outdoors a day after Sizdah Be-dar.